I. Field of the Invention
The present invention relates generally to an apparatus for treating cutaneous vascular lesions and, more particularly, to such an apparatus that readily attaches to the patient. This apparatus in conjunction with the apparatus disclosed in the above applications provide for the treatment of cutaneous vascular lesions by simultaneously cooling the site of the lesions while delivering laser light to the site.
II. Description of the Prior Art
A cutaneous vascular lesion, such as telangiectasia or spider capillaries of the lower extremities, is a condition where previously microscopic blood vessels have become dilated. They are visible through the skin appearing as red, blue or purple variably tortuous lines or patches. The causes of this abnormal enlargement of vessels are not fully understood, and although they are of little medical consequence their cosmetic significance can be great. This is a widespread problem that may cause much concern for those afflicted.
Sclerotherapy is the treatment that is now used. It is considered to be safe, appropriate and relatively effective. Sclerotherapy entails the intravascular injection of one of a variety of agents into the abnormal blood vessels. The substance injected injures the inside of the capillary causing it to shrink or disappear. This treatment is variably painful, approximately seventy percent (70%) effective, and usually requires one to two months waiting before improvement can be seen. There can occur, unpredictably, echymotic or hyperpigmented marks as a side effect. These marks may take many months to fade. Scabbing of injection sites, perhaps due to extravasation of the injected sclerosing agent, may also occur.
The disadvantages of sclerotherapy, as described above, include the pain of treatment, only partial improvement, and the possibility of long term discoloration that can be more noticeable than telangiectasia.
Laser surgery with a variety of different lasers (CO2, Argon, tunable dye, pulsed dye, KTP, Nd/YAG) has been utilized in an attempt to find a less painful, more effective treatment. The desire to avoid side effects has also prompted a search for alternative treatment. To date, the ability to improve the outcome by virtue of laser surgery has, unfortunately, not been possible for reasons explained below.
Although laser surgery (Argon or dye) hurts less than sclerotherapy, it has not offered an improved result. Due to the interaction between laser light and melanin pigments in the epidermis that overlies the target vessels, there can be long term hyperpigmentation, persistent scabs and sometimes permanent scarring.
More recently, medical specialists have attempted to minimize hyperpigmentation, scabs and scarring caused by laser surgery by cooling the lesional site for a given period of time before initiating any treatment by laser surgery. The results of such treatment have proven to be more satisfactory than sclerotherapy or laser surgery alone, as provided in the following two articles.
In Plasti. Reconstr. Surg. 6902:78 (1982) in an article titled "Chilling Port Wine Stains Improves The Response To Argon Laser Therapy" by B. A. Gilchrest, S. Rosen and J. M. Noe, the data obtained in this study suggests the potential benefit of port wine lesional modification by chilling the lesional site by applying ice thereto for 2 to 3 minutes and then subjecting the sites to Argon laser therapy. Ice cubes were applied to the skin surface by enclosing them in an examining glove.
In Plasti. Reconstr. Surg. 75.1:42-45 (1985) in an article titled "The Benefit of Chilling In Argon-Laser Treatment of Port-Wine Stains" by B. Dreno, T. Patrice, P. Litoux and H. Barriere, the authors compare results obtained in Argon laser treatment of port-wine stains with and without preliminary chilling, noting that the success rate is considerably greater with the former procedure (68.6 percent) then with the latter (37.5 percent). For this experiment, an ice bag was applied to port-wine stain for 5 minutes immediately before the beginning of treatment. During the treatment, the ice bag was applied again after 2 minutes of laser use.
It should be noted that in the studies noted in the above articles, Argon laser treatment and cooling did not occur simultaneously, and the Argon laser could not reach the port-wine stain while the examining glove or ice bag covered up the treatment area.
U.S. Pat. No. 3,821,510 to Muncheryan, which issued on Jun. 28, 1974, is directed to a hand-held laser beam transmitting and focusing stylus in which there is provided means for selectively passing therethrough one or more fluids simultaneously with the operation of the device. Since the cooling fluid is passed through a flexible tubing and an upper end of the stylus, the lower end of the stylus that touches the skin provides a small area where cooling may take place.
Although the stylus of Muncheryan provides a laser treatment device that cools a portion of a patient's skin, its cooling elements is confined to the area treated by the laser beam. Also, the cooling element readily dissipates, such that constant replacement is required in order to keep the area cooled. Further, the Muncheryan patent neither recognizes the benefits of cooling a broad area of a patient's skin for treatment, including the minimization of hyperpigmentation, scabs and scarring caused by laser surgery nor the need for a container to maintain the cooling element.
The Muncheryan patent, like all known references, fail to provide an apparatus that contains the cooling medium, yet provides for simultaneous cooling and lasering of a target. Moreover, the present apparatus provides the simultaneous cooling and laser application, but without any obstruction of the path of the laser beam through the apparatus.
The above related priority applications have provided improved methods of treatment by the use of a container to retain the cooling element and to permit the simultaneous cooling and treatment of the target area. However, the container disclosed in these applications failed to appreciate the features of the container of the present application.
Thus, the present invention provides a new laser surgery apparatus to allow for laser photo-coagulation and destruction of cutaneous vascular lesions, such as, for example, lower extremity telangiectasia, while protecting the epidermal compartment from thermal injury that would otherwise result from absorption of laser energy by melanin. Since laser light must pass through the melanin containing epidermis, on its way to the target vessels in the dermis, it is not possible to prevent some degree of heat generation when laser light hits melanin pigment. Indeed, yellow (tunable dye) laser light, although less efficiently absorbed by melanin than is blue-green (Argon) laser light, still causes significant hyperpigmentation as a long term side effect. Thus, cooling dissipates the heat generated by absorption of that light by melanin, thereby minimizing injury to normal skin structures to reduce resulting pain and side effects of scabbing scarring and/or hyperpigmentation. Significantly, the present apparatus permits the epidermis to be cooled simultaneously with the use of laser light, while maximizing the length of time before replacement of the cooling medium and thereby reducing the frequency of replacement of the cooling medium. In addition, the apparatus is constructed such as to minimize obstruction to the path followed by the laser beam.
Thus, the present invention discloses an efficient and economical apparatus for simultaneous cooling during laser treatment of cutaneous vascular lesions. The apparatus can be readily positioned on a large area of the epidermis to be treated, thereby, maximizing the cooling effect during the laser treatment. Further, the apparatus is separate and distinct from the laser beam source so as to utilize present, readily-available laser types without resorting to expensive and complicated devices that integrate laser beams with cooling devices.
Also, the present apparatus permits one to position the cooling medium where desired on the patient. In addition, it permits one to be free to position the laser beam in relation to the apparatus, thus providing needed flexibility.